Regional expression of HOXA4 along the aorta and its potential role in human abdominal aortic aneurysms.

BACKGROUND: The infrarenal abdominal aorta exhibits increased disease susceptibility relative to other aortic regions. Allograft studies exchanging thoracic and abdominal segments showed that regional susceptibility is maintained regardless of location, suggesting substantial roles for embryological origin, tissue composition and site-specific gene expression. RESULTS: We analyzed gene expression with microarrays in baboon aortas, and found that members of the HOX gene family exhibited spatial expression differences. HOXA4 was chosen for further study, since it had decreased expression in the abdominal compared to the thoracic aorta. Western blot analysis from 24 human aortas demonstrated significantly higher HOXA4 protein levels in thoracic compared to abdominal tissues (P < 0.001). Immunohistochemical staining for HOXA4 showed nuclear and perinuclear staining in endothelial and smooth muscle cells in aorta. The HOXA4 transcript levels were significantly decreased in human abdominal aortic aneurysms (AAAs) compared to age-matched non-aneurysmal controls (P < 0.00004). Cultured human aortic endothelial and smooth muscle cells stimulated with INF-γ (an important inflammatory cytokine in AAA pathogenesis) showed decreased levels of HOXA4 protein (P < 0.0007). CONCLUSIONS: Our results demonstrated spatial variation in expression of HOXA4 in human aortas that persisted into adulthood and that downregulation of HOXA4 expression was associated with AAAs, an important aortic disease of the ageing population.

Genome based cell population heterogeneity promotes tumorigenicity: the evolutionary mechanism of cancer.

Cancer progression represents an evolutionary process where overall genome level changes reflect system instability and serve as a driving force for evolving new systems. To illustrate this principle it must be demonstrated that karyotypic heterogeneity (population diversity) directly contributes to tumorigenicity. Five well characterized in vitro tumor progression models representing various types of cancers were selected for such an analysis. The tumorigenicity of each model has been linked to different molecular pathways, and there is no common molecular mechanism shared among them. According to our hypothesis that genome level heterogeneity is a key to cancer evolution, we expect to reveal that the common link of tumorigenicity between these diverse models is elevated genome diversity. Spectral karyotyping (SKY) was used to compare the degree of karyotypic heterogeneity displayed in various sublines of these five models. The cell population diversity was determined by scoring type and frequencies of clonal and non-clonal chromosome aberrations (CCAs and NCCAs). The tumorigenicity of these models has been separately analyzed. As expected, the highest level of NCCAs was detected coupled with the strongest tumorigenicity among all models analyzed. The karyotypic heterogeneity of both benign hyperplastic lesions and premalignant dysplastic tissues were further analyzed to support this conclusion. This common link between elevated NCCAs and increased tumorigenicity suggests an evolutionary causative relationship between system instability, population diversity, and cancer evolution. This study reconciles the difference between evolutionary and molecular mechanisms of cancer and suggests that NCCAs can serve as a biomarker to monitor the probability of cancer progression.

Evidence for association between the HLA-DQA locus and abdominal aortic aneurysms in the Belgian population: a case control study.

BACKGROUND: Chronic inflammation and autoimmunity likely contribute to the pathogenesis of abdominal aortic aneurysms (AAAs). The aim of this study was to investigate the role of autoimmunity in the etiology of AAAs using a genetic association study approach with HLA polymorphisms. METHODS: HLA-DQA1, -DQB1, -DRB1 and -DRB3-5 alleles were determined in 387 AAA cases (180 Belgian and 207 Canadian) and 426 controls (269 Belgian and 157 Canadian) by a PCR and single-strand oligonucleotide probe hybridization assay. RESULTS: We observed a potential association with the HLA-DQA1 locus among Belgian males (empirical p = 0.027, asymptotic p = 0.071). Specifically, there was a significant difference in the HLA-DQA1*0102 allele frequencies between AAA cases (67/322 alleles, 20.8%) and controls (44/356 alleles, 12.4%) in Belgian males (empirical p = 0.019, asymptotic p = 0.003). In haplotype analyses, marginally significant association was found between AAA and haplotype HLA-DQA1-DRB1 (p = 0.049 with global score statistics and p = 0.002 with haplotype-specific score statistics). CONCLUSION: This study showed potential evidence that the HLA-DQA1 locus harbors a genetic risk factor for AAAs suggesting that autoimmunity plays a role in the pathogenesis of AAAs.

HLA-DQA is associated with abdominal aortic aneurysms in the Belgian population.

Chronic inflammation and autoimmunity likely contribute to the pathogenesis of abdominal aortic aneurysms (AAAs). The aim of this study was to investigate the role of autoimmunity in the etiology of AAAs using a genetic association study approach with human leukocyte antigen (HLA) polymorphisms (HLA-DQA1, -DQB1, -DRB1 and -DRB3-5 alleles) in 387 AAA cases and 426 controls. We observed an association with the HLA-DQA1 locus among Belgian males, and found a significant difference in the HLA-DQA1*0102 allele frequencies between AAA cases and controls. In conclusion, this study showed potential evidence that the HLA-DQA1 locus harbors a genetic risk factor for AAAs suggesting that autoimmunity plays a role in the pathogenesis of AAAs.

Sequential molecular and cellular events during neoplastic progression: a mouse syngeneic ovarian cancer model.

Studies performed to identify early events of ovarian cancer and to establish molecular markers to support of early detection and the development of chemopreventive regimens have been hindered by a lack of adequate cell models. Taking advantage of the spontaneous transformation of mouse ovarian surface epithelial (MOSE) cells in culture, we isolated and characterized distinct transitional stages of ovarian cancer as the cells progressed from a premalignant nontumorigenic phenotype to a highly aggressive malignant phenotype. Transitional stages were concurrent with progressive increases in proliferation, anchorage-independent growth capacity, in vivo tumor formation, and aneuploidy. During neoplastic progression, our ovarian cancer model underwent distinct remodeling of the actin cytoskeleton and focal adhesion complexes, concomitant with downregulation and/or aberrant subcellular localization of two tumor-suppressor proteins E-cadherin and connexin-43. In addition, we demonstrate that epigenetic silencing of E-cadherin through promoter methylation is associated with neoplastic progression of our ovarian cancer model. These results establish critical interactions between cellular cytoskeletal remodeling and epigenetic silencing events in the progression of ovarian cancer. Thus, our MOSE model provides an excellent tool to identify both cellular and molecular changes in the early and late stages of ovarian cancer, to evaluate their regulation, and to determine their significance in an immunocompetent in vivo environment.

Tight junction proteins claudin-3 and claudin-4 are frequently overexpressed in ovarian cancer but not in ovarian cystadenomas.

PURPOSE: Claudin proteins represent a large family of integral membrane proteins crucial for tight junction (TJ) formation and function. Claudins have been shown to be up-regulated in various cancers and have been suggested as possible biomarkers and targets for cancer therapy. Because claudin-3 and claudin-4 have been proposed to be expressed in epithelial ovarian cancer, we have performed a detailed analysis of CLDN3 and CLDN4 expression in a panel of ovarian tumors of various subtypes and cell lines. We also investigated whether high expression of claudin-3 and claudin-4 was associated with TJ function in ovarian cancer cells. EXPERIMENTAL DESIGN: RNA was obtained from a panel of 39 microdissected epithelial ovarian tumors of various histological subtypes for real-time reverse transcription-PCR analysis. In addition, a total of 70 cases of ovarian carcinomas, ovarian cysts, and normal ovarian epithelium from a tissue array were analyzed by immunohistochemistry. Finally, a panel of cell lines was used for Western analysis of claudin expression and TJ permeability studies. RESULTS: Although expressed at low levels in some normal human tissues, including the ovary, CLDN3 and CLDN4 are highly up-regulated in epithelial ovarian cancers of all subtypes. Immunohistochemical analyses using our ovarian tissue array confirmed the high level of expression of claudin-3 and claudin-4 in the majority of ovarian carcinomas, including many tumors exhibiting cytoplasmic staining. Ovarian cystadenoma did not frequently overexpress these proteins, suggesting that the expression of these proteins is associated with malignancy. In ovarian cancer cell lines, claudin-3 and claudin-4 expression was not associated with functional TJs as measured by transepithelial electrical resistance. CONCLUSIONS: These results show that CLDN3 and CLDN4 are frequently up-regulated in ovarian tumors and cell lines and may represent novel markers for this disease. Overexpression of these genes in ovarian cancer also suggests interesting scenarios for the involvement of TJ in tumorigenesis. A better knowledge of the mechanisms underlying ovarian tumorigenesis will likely result in the development of novel approaches for the diagnosis and therapy of this deadly disease.

Human papillomavirus (HPV) transcripts in malignant inverted papilloma are from integrated HPV DNA.

OBJECTIVES: The objectives of the study were to detect human papillomavirus (HPV) sequences in nasal inverted papilloma (IP) lesions and to determine whether HPV is involved in the progression of IP to sinonasal squamous cell carcinoma (SCC). STUDY DESIGN: A retrospective study was performed on 14 patients diagnosed with IP within the last 12 years. Three of these 14 patients developed SCC. METHODS: Eighteen formalin-fixed, paraffin-embedded tissue blocks were obtained for these 14 patients. After DNA extraction, polymerase chain reaction (PCR) was performed, followed by hybridization using HPV 6, 11, 16, 18, 31, 33, 35, 45, and 52 specific DNA probes, in an attempt to identify HPV type in each specimen. After RNA extraction, the integration status of the HPV genome was evaluated based on the relative abundance of E7 and E5 viral transcripts, assessed by quantitative real-time PCR. RESULTS: HPV sequences were detected in samples from 3 of the 14 patients with IP. Of the three patients with SCC, HPV sequences were detected in two patients, whereas one patient was negative for the oligoprobes tested. Of the 11 patients diagnosed only with IP, 1 patient was positive for HPV DNA (HPV type 11). This difference in HPV positivity between IP and SCC was not statistically significant (P = .09, Fisher's Exact test, two tailed). Viral transcripts were detected in both patients with SSC who were HPV positive. Because HPV early transcripts are polycistronic, loss of 3' transcript sequences (E5) and retention of 5' sequences (E7) indicates integration. One of the SSC containing HPV 18 sequences showed a E7/E5 ratio of 776:1. The other SSC showed E7 transcripts and an absence of E5 transcripts CONCLUSION: HPV transcripts were present in SCC positive for HPV, and the relative level of E7 to E5 transcripts indicates integration of the viral genome. These findings are suggestive of HPV having an active role in the lesion. More extensive studies are needed to determine the exact role of HPV in IP and progression to SCC.

Integration of human papillomavirus type 11 in recurrent respiratory papilloma-associated cancer.

OBJECTIVES/HYPOTHESIS: The main objective was to demonstrate that human papillomavirus (HPV) type 11 is an aggressive virus that plays a significant role in the development of laryngeal cancer in patients with a history of recurrent respiratory papillomatosis (RRP). We have done so by preliminary investigation into the molecular mechanism underlying the malignant transformation of RRP to invasive squamous cell carcinoma. STUDY DESIGN: An experimental, nonrandomized, retrospective study using tissue specimens from nine patients with a history of RRP that progressed to laryngeal or bronchogenic cancer was performed. METHODS: DNA and RNA were extracted from 20 formalin-fixed, paraffin-embedded specimens from six patients with a history of early onset RRP and laryngeal cancer and from three patients with early onset RRP and bronchogenic cancer. Polymerase chain reaction (PCR) was performed on DNA to determine the HPV type in each specimen. Reverse-transcriptase PCR specific for virus transcripts was performed on RNA to determine whether the viral genome was integrated into the host genome. RESULTS: HPV-11 but not HPV-6, 16, or 18 was found in all of the laryngeal and bronchogenic cancers in patients with a history of early onset RRP in this study. RNA, sufficiently intact for examination, was obtained from seven patients. Analysis of HPV 11 transcripts revealed integration of the viral genome in three of seven patients. CONCLUSIONS: HPV type 6 and 11 are considered "low-risk" viruses and are not associated with genital cancers, as are HPV types 16 and 18. However, our data suggests that HPV type 11 is an aggressive virus in laryngeal papilloma that should be monitored in patients with RRP.

HLA-DQ alleles in white and African American patients with juvenile-onset recurrent respiratory papillomatosis.

OBJECTIVE: To determine HLA-DQalpha and -DQbeta1 allele associations in juvenile-onset recurrent respiratory papillomatosis (RRP) for risk, disease course, and human papillomavirus type. DESIGN: A nonrandomized controlled study was performed on DNA extracted from papilloma specimens of children with a history of RRP, and from peripheral blood of African American and white children without RRP. The frequencies of DQalpha and DQbeta1 alleles were compared between patients and ethnically matched controls. SUBJECTS: Records of 48 children treated for RRP at Children's Hospital of Michigan in Detroit (26 African American and 22 white) were reviewed. Control subjects consisted of 80 African American and 80 white children seen at the hospital for conditions other than RRP. RESULTS: African American and white patients with DQbeta1*050X (not *0501, *0502, *0503, *0504, or *0505) were at higher risk to develop RRP than controls (P =.01 and.03, respectively). DQbeta1*0402 was protective for African Americans (P =.01). Whites with DQalpha*0102 were at risk for RRP (P =.03). This allele was associated with disease remission in African Americans (P =.03). DQalpha*0101/0104 conferred protection in whites (P =.047). No association was seen for allele frequency and human papillomavirus type. Whites with haplotype DQalpha*0501/DQbeta1*0201 were at high risk for RRP (P =.002). No relationships were seen for African Americans or whites between haplotype frequencies and disease course or human papillomavirus type. CONCLUSIONS: HLA-DQalpha and -DQbeta1 alleles occur at different frequencies in African American and white children with RRP than controls. Specific alleles influence risk for RRP. Allele and haplotype frequencies have some influence on disease course, but were independent of human papillomavirus type.

Radiation-induced epigenetic DNA methylation modification of radiation-response pathways.

DNA methylation can regulate gene expression and has been shown to modulate cancer cell biology and chemotherapy resistance. Therapeutic radiation results in a biological response to counter the subsequent DNA damage and genomic stress in order to avoid cell death. In this study, we analyzed DNA methylation changes at>450,000 loci to determine a potential epigenetic response to ionizing radiation in MDA-MB-231 cells. Cells were irradiated at 2 and 6 Gy and analyzed at 7 time points from 1-72 h. Significantly differentially methylated genes were enriched in gene ontology categories relating to cell cycle, DNA repair, and apoptosis pathways. The degree of differential methylation of these pathways varied with radiation dose and time post-irradiation in a manner consistent with classical biological responses to radiation. A cell cycle arrest was observed 24 h post-irradiation and DNA damage, as measured by γH2AX, resolved at 24 h. In addition, cells showed low levels of apoptosis 2-48 h post-6 Gy and cellular senescence became significant at 72 h post-irradiation. These DNA methylation changes suggest an epigenetic role in the cellular response to radiation.

Human papillomavirus, cervical cancer and women's knowledge.

BACKGROUND: Human papillomavirus (HPV) is the major risk factor for cervical cancer. METHODS: We implemented a retrospective case-series study to discern HPV knowledge accuracy among women diagnosed with and treated for cervical cancer. Cases (n=1174), identified from the Pathology database, were diagnosed and treated for cervical cancer at the same institution. Data were collected using self-administered questionnaires and by reviewing medical records. RESULTS: A total of 328 (27.9%) women returned the completed forms. Only 19% of the respondents had identified HPV as the primary risk factor for cervical cancer. Environmental pollutants, radiation exposure, poor dietary habits, excessive physical activity and family history of cervical cancer were listed as risk factors among many others. Multivariate analysis was performed to determine variables that were best associated with HPV knowledge accuracy. Age and education were the two variables that were statistically associated with the outcome. Younger and more educated women who participated in this study were more likely to know about the association between HPV infection and the risk of cervical cancer. CONCLUSIONS: Cervical cancer risk factor knowledge, especially knowledge about HPV is low, even among women with the history of cervical cancer. Younger and more educated women are more likely to have HPV and cervical cancer knowledge accuracy. The importance of personal health practices and the focus on health education should be equally emphasized to achieve successful cancer prevention through vaccination.